Vehicle occupant protection systems typically includes an inflatable device, such as an air bag, that is inflatable for helping to protect an occupant of a vehicle. Some vehicle occupant protection systems control the inflatable device in response to occupancy of the seat, a determination of whether an object on the seat is animate or inanimate, a determination that a reward facing child seat is present on the seat, and/or a determination of an occupant's position, weight, size, etc. An exemplary vehicle occupant protection system is disclosed in U.S. Pat. No. 5,330,226.
Some vehicle occupant protection systems use cameras to determine the location of the occupant in the passenger compartment of the vehicle. Inflation of the inflatable device is controlled in response to the determined occupant location. At times, the view of the cameras into the passenger compartment may become obstructed. For example, if the occupant is reading a newspaper, the view of the cameras into the passenger compartment may be obstructed. Excessive dirt or other substances on a housing for the cameras may also obstruct the view of the cameras into the passenger compartment. Additionally, changes in temperatures, vibrations, and other factors that are frequency experienced by vehicles may cause the cameras to come out of calibration. When the cameras come out of calibration, the determined location of the passenger may be erroneous. Thus, it is desirable to prevent an erroneous determination of the location of the occupant in response to the view of the cameras becoming obstructed or the cameras coming out of calibration.